import tkinter as tk
import time
root = tk.Tk()
root.title("YOLO")
root.iconbitmap('qianduan\logo.ico')
root.geometry('450x450+100+100')
root.resizable(0,0)
root.title("我们的时钟")

def gettime():
  dstr.set(time.strftime("%H:%M:%S"))
  root.after(1000,gettime)

dstr = tk.StringVar()

lb= tk.Label(root,textvariable=dstr,fg='green',font=("微软雅黑",85))

lb.pack()
gettime()

root.mainloop()